Process for producing highly refined antidetonation motor fuel



Pat ented Oct. 1, 1935 PROCESS "FOR ".PRoDUcrNG HIGHLY RE FINED.ANTIDETONATION MOTOR FUEL .Norman'ffink Black and an av rsion, (BatonRou La, assigno (to Standard-Infi- 1 lN Erawing, A plication Ma-yfi, 1 aserial-Natures n Claims (curse-.40)

"This invention relates to the preparation of highly refined motor fueland more specifically comprises an-improved method of finishingmotorfuel which has been prepared by =theflhydrogenation-of higher-boilinghydrocarbons.

Our improved process will 'be fully understood from the followingdescription.

Hydrocarbon oils, higher boiling than are suitable for motor-fuel; areheated to a temperature .in excess of 350 F5andare forced into-areaction chamber which is maintained *under pressure in excess; of 20-atmospheres, preferably 100 or "200 atmospheres or higher, and attemperatures between-about 900 and 1 100" F.

Hydrogen or agas r'ich in free hydrogen is'also forced. into thea'eaction-chamb'er and --is preferably added in admixture with the oil.=I-nt-he reaction chamber the higher boiling hydrocarbons are subjectedto hydrccycliformation and are substantially l completely-converted =tohydrocarbons :boiling below about 450 F. -Such hydrocarbons as arelnotconverted on one passage through the reaction chamber maybe continuouslyrecycled. I l

' The :reaction chamber preferably contains a catalytic material "whichgreatly increases the rate of hydrocycliformation. "Theoxides or-sul-:fides of metals of the 11, IV, -and groups of the=periodic system -aresuitable oatalytic materials for this purpose, among @hich -thaoxides orsulfides of chromium, tungsten and molybdenum, preferably in combinationwith the oxides of zinc or magnesium, are especially satisfactory. Allof these materials are immune to sulfur poisoning.

Vapors flowing out of the reaction chamber are cooled, preferably byinterchange of heat with cold feed material, and by further cooling ifnecessary and uncondensed gases are separated from the liquid products.The uncondensed gases which contain a substantial quantity of unusedhydrogen may be scrubbed with oil, acid or alkali on any combinations ofthese to rid them of hydrogen sulfide, ammonia, hydrocarbon gases andother impurities and the purified gas may be recirculated to thereaction chamber.

The liquid products may then be passed into a fractionating towerwherein they may -be sepdrocarbons boiling below about 450, 400, or

850 F. and the other containing hyc'lrocarbons of higher boiling pointrange. The latter-fra'c tion may be recirculated to the reaction chamberfor zfurtheritreatment.

The lighteraraction suitable for motor fuel 5 andisecharactenizedzbyexceptionally low sulfur and gum content and has marked anti-detonationcharacteristics. -We'have found that it may be still morehighly refinedand at thesame time :have its anti-"detonation properties even further10 increased bysubjecting it ;to the :following finish- ;ing treatment:

.The hydrogenatedoil -is treated .with sulfuric acid i 1 :trelatively:low: temperatu es. :Between .aboutzranm5- pon ds 3 su fur a e barrelpreferab e and temper t r should maintained below about 80 andpreferably .about 35; F. A greater amount ,of acid ,or a. highertemperature of trea ment .may b used, but the resultsara ot :asso d as.thQse a n d @under .the preferred conditions. F ll wi th .acid.treatrnentthe ,excess acid is neutralized by .the addition-bf taaalkeli2 causti soda J o lye and the mixture .is .then subjected to fire and vsteam distillation. The maximum temperature to which the oilis heatedduring the distillation is preferably notabove about 300 F. Thedistillation maybe carried out in the presence of clamauch as ;forexample Atapulgusclay. About 4 pounds :of .:200..mesh.clay .pe'r ibarrel.of oil is suiji'cient ,but more or less-than this. ,may be used :withsatisfactory .results.

As amexamplepf this methodof finishing -hy-1 drogenated. motor fuel, a400 F. E. P. distillate is separated from the product ofhydrocycliformation of a Mid-Continent gas oil of boiling range 450 to600 F. This distillate has the following characteristics:

Gravity A. P. I 51.6

It is treated with 2 pounds of 98% sulfuric acid per barrel of oil at atemperature of 80 F. The acid is neutralized by the addition of causticalkali and the mixture is steam distilled at a maximum oil temperatureof 300 F. The finished distillate thus obtained has the followingcharacteristics:

Gravity A. P. I 53.0 Octane number 74.8 Gum (porcelain dish) 12.4 mg.

Color (Robinson) +25 Initial boiling point 120 F. Final boiling point391 F. Sulfur 04% The octane number is the percent of iso-octane whichmust be added to normal heptane to give a mixture having the sameanti-detonation value as the motor fuel. Thus the higher the octanenumber, the greater is the anti-detonation value of the fuel.

It will be observed that the color and gum have been markedly improvedand that the octane number has been increased from 69.0 to 74.8 which isa substantial improvement.

To show the effect of the temperature at which the acid treatment iscarried out, a 300 F. E. P..

distillate obtained from the hydrocycliformation of the sameMid-Continent gas oil is treated at 35? F. and 80 F. respectively withthe following It will be observed that when the acid treatment iscarried out at 35 F. the increase in octane number is greater than it iswhen the acid treatment is at 80 F.

As a second example a. 432 F. E. P. gasoline separated from the productof hydrocycliformation of the heavy naphtha bottoms of Coastal crude istreated-with 2 pounds 98% sulfuric acid per barrel at a temperature of80 F. and fire and steam distilled. The characteristics of the oilbefore and after treatment are as follows:

Untreated Treated Gravity A. P. I 38.1 38. 3 85.6

It will be observed that with this motor fuel also which was obtained bythe hydrocycliformation of an entirely different type of gas oil thanthe one in the previous example, the color and gum have been markedlyimproved and the octane 5 number has also been substantially increased,from 83.6 to 85.6.

We are aware that the acid treatment of straight-run or cracked gasolinegenerally causes a. decrease in the anti-detonation value of the motorfuel, and while we are not able to state the exact reasons for theopposite behavior of hydrogenated gasolines in this respect, we havefound that the acid. treatment of the hydrogenated motor fuels carriedout in the m'anher described consistently results in an increase in theanti-detonation value. This effect is particularly noticeable with motorfuels produced in a vapor phase hydrogenation or hydrocycliformationprocess which is intended to denote a process of destructive hydrocarboncarried out at temperatures above 900 F. and with a pressure of hydrogenadapted to produce largely unsaturated products on the one hand, and toprevent coke and tar formation on the other. In most cases thehydrogenated motor fuels are sufficiently refined by the hydrogentreatment in respect to color and gum forming properties, and theadditional acid treatment is not usually necessary for finishingpurposes, or at most is only necessary to a more limited extent thanwith the cracked gasolines. The fact however, that the acid treatmentalso causes a substantial increase in the anti-detonation value of thehydrogenated motor fuel makes such treatment especially desirable.

This invention is not limited by any theory of the mechanism of thereactions nor by any examples given merely for purposes of illustration,but only by the following claims in which we wish to claim all noveltyinherent in the invention.

We claim:

1. An improved process for finishing naphthas of the type of gasolineand prepared by destructive hydrogenation of high boiling hydrocarbonswhich comprises treating the naphtha with sulfuric acid of substantially98% strength at a temperature from about 35 to 80 F. whereby the naphthais improved with respect to color and gum content and itsanti-detonation value remains undiminished.

2. The process according to claim 1 in which 2 to 5 pounds of sulfuricacid per barrel of oil is used for treating.

NORMAN F. BLACK. J. ATWOOD TILTON.

